This invention concerns composite assembly units for vehicle bodies and a method and an apparatus for producing such composite assembly units. In particular, the invention concerns a glass cover for sliding roofs of the type fitted in mass produced cars.
The composite assembly units designed in accordance with the invention are basically suitable for all external and internal plate-like or pane-like structures in vehicle bodies whether transparent or opaque, including hoods, doors and lids/covers. If the following text constantly refers to vehicle roofs and vehicle roof components, this is so because this is in fact the preferred application for the invention without, however, meaning to put a limit to its application. Furthermore, the term xe2x80x9csliding roofxe2x80x9d is not intended to extend to those structures alone in which the panel, after lowering its rear edge to open the roof, can slide underneath the rear fixed roof panel but also to sliding roofs where at least one of the panels can be swung from its closed position at the pivot point provided near its front edge to swing it up above the fixed roof panel. Swing-out lids similar to ventilation flaps hinged at the front and what are called top ridge sliding roofs where, after lifting it rear edge the panel is partly slidable over the rear fixed roof panel to open the roof, are also to be included.
Such composite assembly units as a rule require a seal at adjoining vehicle body parts or other covers/panels. Such a seal can be a permanent seal at an adjoining vehicle body part formed after fitting the composite assembly unit in question, for example the edge seal of a prefabricated roof module against the roof frame of a vehicle body or a temporary seal of the composite assembly unit against an adjoining body component, as is found for example between the cover and the roof opening edges of a sliding roof structure in a vehicle.
Seals in the designs in question are as a rule arranged at the edges or near the edges of the composite assembly units to prevent ingress of moisture and/or dirt into gaps between adjoining vehicle body parts. According to the state of the art, rubber-like seal sections are fitted for this purpose to protrusions or edges of the composite assembly unit (FR 2 529 844 A, DE 44 22 176 C1) or inserted into grooves provided on the composite assembly unit (DE 196 37 793 C1) so that they rest tightly against the adjoining vehicle body part when the composite assembly unit is fitted in position. In the case of other known versions, grooves are provided in the composite assembly unit to take adhesive beading to seal the composite assembly unit at the adjoining vehicle body part (DE 32 02 594 C2). Arrangements are also proposed in which seals are placed between the composite assembly unit and the vehicle body part during assembly (DE 29 29 915 A1, DE 79 29 367 U1). The need for fitting the necessary seals/seal sections after producing the composite assembly units in an expensive way in additional stages before fitting at the vehicle body is common to all these arrangements.
Therefore, a composite assembly unit for vehicle bodies has already been proposed in the same applicant""s earlier patent application DE 199 46 008 A1, where a rigid layer and a layer of plastic foam is applied to the inner side of the rigid layer, a seal being applied with foam to the edge of the plastic layer. As a result, after applying foam to the plastic layer on the inside of the rigid layer, the composite assembly unit is already provided with an integrated seal. Therefore, the need for forming a locating edge or protrusion at the composite assembly unit and fitting an additional seal initially provided separately onto the finished composite assembly unit is eliminated to advantage, making it possible to produce a ready-to-fit composite assembly unit at a low cost. The same applies to the design known from document DE 43 26 013 A1.
Finally, document DE 196 30 177 A1 discloses a rigid lid for closing an opening in a vehicle body. The lid has a flat base body, preferably made from a transparent material, the edge portion of which is provided with a frame made from plastic. Further, a surrounding seal for sealing a gap between the lid and the vehicle body is mounted to the lid. The seal comprises a sealing section and a fixing section, the latter being inserted between the base body and the plastic frame. An elastic deformation of the fixing section between the base body and the plastic frame cannot be taken from this prior art.
Further problems which occur with the abovementioned versions emerge due to the fact that the seals placed over or into the composite assembly unit can protrude out of the composite assembly unit to the outside of the vehicle body due to unavoidable tolerances. This projecting seal results in, for example, rain water possibly being retained over vehicle body areas delineated by such seals; an undesirable layer of dirt remains over such areas of the body after this water evaporates. On the other hand, the protruding seal forms an undesirable noise-generating edge. Remedy could only be found here so far by applying an expensive method of grinding the seal off or grinding it down flush after assembly at the composite assembly unit.
The object of this invention is to create a composite assembly unit at which a defined, in particular flush finish position between the flat base body and the seal can be guaranteed by simple means, and a method and an apparatus for producing such a composite assembly unit in a simple way.
According to the invention, a composite assembly unit for closing an aperture in a vehicle body, in particular a glass panel for a sliding roof, comprises a flat base body, preferably a glass or plastic pane, having an outside face and an inside face, and a seal for sealing a gap between the composite assembly unit and the vehicle body, the seal having a sealing section and a fixing section, and being attached to the base body by means of plastic foam, wherein the fixing section of the seal is pressed under elastic deformation by the plastic foam against the inside face of the base body so that the sealing section of the seal terminates substantially flush with the outside face of the base body.
The following stages are envisaged within the method of manufacturing the composite assembly unit according to the invention:
placing the base body and the seal in a foam application tool,
holding the sealing section of the seal substantially flush with the outside face of the base body,
pressing the fixing section of the seal to the inside face of the base body, and
attaching the seal to the base body by applying the plastic foam and removing the composite assembly unit from the foam application tool.
The apparatus for implementing this method according to the invention has finally a foam application tool comprising two mold halves for accommodating the base body and the seal, the mold half imparting a shape to the plastic foam having a protrusion in the area of the seal forcing the fixing section of the seal against the inner face of the base body when the foam application tool is closed, while the other half of the mold has a retaining section in the area of the seal, which holds the sealing section of the seal substantially flush with the outside face of the base body when the foam application tool is closed.
As a result, by flexibly pressing the fixing section of the seal against the inside face of the base body, which goes hand in hand with an appropriate elastic deformation of the fixing section, the tolerances between the participant parts are compensated, thus taking care of a constant, accurate and mainly flush finish on the outside between the base body and the seal without any additional expensive operations having to be done to achieve this. Thus, not only is the seal affixed to the base body by applying foam at the back but a specific relative position between the base body and the seal is also achieved when the composite assembly unit is produced to advantage in a single operation (what is called a xe2x80x9cone-shot-systemxe2x80x9d).
The sealing section of the seal can rest directly on the edge of the base body. The direct contact of the seal with the base body is not only satisfactory from the point of view of appearance. This arrangement also takes up very little space which in the case of a glass panel of a sliding roof not only provides the advantage of a larger viewing area but also reduces the dimension of the gap between the panel and the vehicle body.
The seal can be annular and, when not fitted to the base body, can have a length measured on the inside of the sealing section which is shorter than the peripheral length of the base body edge. This allows the seal to be fitted onto the edge of the base body first simply by flexibly expanding it before the base body and the seal are placed into the foam application tool.
The sealing section of the seal can in principle be formed as a solid section from one material with appropriate elastic properties. However, it is preferred also for reasons of cost and weight that the sealing section has a hollow profile.
The fixing section of the seal can have a plurality of projections on its side facing the inside of the base body, that is, in the form of ribs extending all round, resting against the inside face of the base body. Elastic properties of the fixing section required for reliable tolerance compensation are easy to set at the required level in a specified way by providing the suitable geometry. At the same time, the protrusions provide locally increased surface pressure in the foam application tool between the fixing section of the seal and the base body, thus forming a reliable tight seal between the fixing section and the base body so that the foam which is initially fluid cannot pass through at this point.
The fixing section of the seal can be provided with ribs on its side facing away from the inside face of the base body, which ribs positively and detachably engage in undercut depressions in the plastic foam formed by the application of foam. The fixing section is given what is called a fir-tree profile to ensure secure seating of the seal offering protection against unintentional removal from the hardened plastic foam.
The seal can have a plurality of suitable metallic grid elements distributed over its periphery, stiffening a part section of the sealing section which rests against the edge of the base body, and the fixing section of the seal. These grid elements can be usefully introduced into the seal in production already at the extrusion stage, running simultaneously through the extruder gap in the form of a grid band while being initially connected for example in a symmetrical arrangement by means of a center web before the connecting center web is broken or cut away to form two seal strips which are stiffened but remain elastic in the longitudinal direction. An armored annular seal will be produced by cutting such a seal strip to size and bonding or welding its ends together, capable of being elastically stretched and easily fitted on to the edge of the base body before the base body with the seal on it is introduced into the foam application tool. It is also possible to insert what is known as a longitudinally expandable meander grid strip.
The seal can also have a lip section, also stiffened by grid elements, protruding between the sealing section and the fixing section, the width of the sealing section being adjustable by bending the lip section according to or to suit the width of the gap between the composite assembly unit and the vehicle body.
When applying foam to the base body, the seal can to advantage be a seal element between the mold halves of the foam application tool so that the foam application tool does not need to have its own wearing seal.
A seal can be used consisting of an elastomeric material such as expanded rubber or EPDM (ethylene propylene diene polymethylene) which does not bind when applying the foam material, preferably PUR (polyurethane), allowing the seal to be replaced.
Finally, it must be mentioned with regard to the apparatus that one of the mold halves of the foam application tool can, to advantage, have a bevel in the area of the seal which presses the sealing section of the seal against the edge of the base body when the foam application tool is closed.
In summary, the invention may be defined as follows:
According to a first aspect of the present invention, there is provided a composite assembly unit for closing an aperture in a vehicle body, the unit comprising a flat base body, the base body having an outside face and an inside face, there being a seal for sealing a gap between the composite assembly unit and the vehicle body, the seal having a sealing section and a fixing section, and being attached to the base body by means of plastic foam, wherein the fixing section of the seal is pressed under elastic deformation by the plastic foam against the inside face of the base body so that the sealing section of the seal terminates substantially flush with the outside face of the base body.
According to a second aspect of the present invention, there is provided a method for producing a composite assembly unit for closing an aperture in a vehicle body, the unit comprising a flat base body, the base body having an outside face and an inside face, there being a seal for sealing a gap between the composite assembly unit and the vehicle body, the seal having a sealing section and a fixing section, and being attached to the base body by means of plastic foam, wherein the fixing section of the seal is pressed under elastic deformation by the plastic foam against the inside face of the base body so that the sealing section of the seal terminates substantially flush with the outside face of the base body; wherein the method comprises the following steps:
placing the base body and the seal in a foam application tool,
holding the sealing section of the seal substantially flush with the outside face of the base body,
pressing the fixing section of the seal to the inside face of the base body, and
attaching the seal to the base body by applying the plastic foam and removing the composite assembly unit from the foam application tool.
According to a third aspect of the present invention, there is provided an apparatus for producing a composite assembly unit for closing an aperture in a vehicle body, the unit comprising a flat base body, the base body having an outside face and an inside face, there being a seal for sealing a gap between the composite assembly unit and the vehicle body, the seal having a sealing section and a fixing section, and being attached to the base body by means of plastic foam, wherein the fixing section of the seal is pressed under elastic deformation by the plastic foam against the inside face of the base body so that the sealing section of the seal terminates substantially flush with the outside face of the base body, the composite assembly unit being produced by a method comprising the following steps:
placing the base body and the seal in a foam application tool,
holding the sealing section of the seal substantially flush with the outside face of the base body,
pressing the fixing section of the seal to the inside face of the base body, and
attaching the seal to the base body by applying the plastic foam and removing the composite assembly unit from the foam application tool; wherein the apparatus comprises a foam application tool having two mold halves for accommodating the base body and the seal, one mold half imparting a shape to the plastic foam having a protrusion in the area of the seal which presses the fixing section of the seal against the inside face of the base body when the foam application tool is closed, and the other mold half having a holding section in the area of the seal, which holds the sealing section of the seal substantially flush with the outside face of the base body when the foam application tool is closed.